Improvement of leaf rust resistance in bread wheat variety DWR162 (Triticum aestivumL.) through marker assisted selection

Abstract We report the map-based cloning of the leaf rust resistance gene Lr21, previously mapped to a generich region at the distal end of chromosome arm 1DS of bread wheat (Triticum aestivum L.). Molecular cloning of Lr21 was facilitated by diploid/polyploid shuttle mapping strategy. Cloning of Lr21 was confirmed by genetic transformation and by a stably inherited resistance phenotype in transgenic plants. Lr21 spans 4318 bp and encodes a 1080-amino-acid protein containing a conserved nucleotide-binding site (NBS) domain, 13 imperfect leucine-rich repeats (LRRs), and a unique 151-amino-acid sequence missing from known NBS-LRR proteins at the N terminus. Fine-structure genetic analysis at the Lr21 locus detected a noncrossover (recombination without exchange of flanking markers) within a 1415-bp region resulting from either a gene conversion tract of at least 191 bp or a double crossover. The successful map-based cloning approach as demonstrated here now opens the door for cloning of many crop-specific agronomic traits located in the gene-rich regions of bread wheat.

Download Full-text

Molecular mapping of adult-plant race-specific leaf rust resistance gene Lr12 in bread wheat

Molecular Breeding ◽

10.1007/s11032-010-9467-4 ◽

2010 ◽

Vol 28 (2) ◽

pp. 137-142 ◽

Cited By ~ 26

Author(s):

S. Singh ◽

Robert L. Bowden

Keyword(s):

Leaf Rust ◽

Resistance Gene ◽

Bread Wheat ◽

Rust Resistance ◽

Molecular Mapping ◽

Leaf Rust Resistance ◽

Rust Resistance Gene ◽

Adult Plant ◽

Leaf Rust Resistance Gene

Download Full-text

Cytogenetic analysis and mapping of leaf rust resistance in Aegilops speltoides Tausch derived bread wheat line Selection2427 carrying putative gametocidal gene(s)

Genome ◽

10.1139/gen-2017-0107 ◽

2017 ◽

Vol 60 (12) ◽

pp. 1076-1085 ◽

Cited By ~ 2

Author(s):

M. Niranjana ◽

Vinod ◽

J.B. Sharma ◽

Niharika Mallick ◽

S.M.S. Tomar ◽

...

Keyword(s):

Leaf Rust ◽

Bread Wheat ◽

Rust Resistance ◽

Dominant Gene ◽

Puccinia Triticina ◽

Leaf Rust Resistance ◽

Aegilops Speltoides ◽

Lr Genes ◽

Gametocidal Gene ◽

Chromosome 3B

Leaf rust (Puccinia triticina) is a major biotic stress affecting wheat yields worldwide. Host-plant resistance is the best method for controlling leaf rust. Aegilops speltoides is a good source of resistance against wheat rusts. To date, five Lr genes, Lr28, Lr35, Lr36, Lr47, and Lr51, have been transferred from Ae. speltoides to bread wheat. In Selection2427, a bread wheat introgresed line with Ae. speltoides as the donor parent, a dominant gene for leaf rust resistance was mapped to the long arm of chromosome 3B (LrS2427). None of the Lr genes introgressed from Ae. speltoides have been mapped to chromosome 3B. Since none of the designated seedling leaf rust resistance genes have been located on chromosome 3B, LrS2427 seems to be a novel gene. Selection2427 showed a unique property typical of gametocidal genes, that when crossed to other bread wheat cultivars, the F1 showed partial pollen sterility and poor seed setting, whilst Selection2427 showed reasonable male and female fertility. Accidental co-transfer of gametocidal genes with LrS2427 may have occurred in Selection2427. Though LrS2427 did not show any segregation distortion and assorted independently of putative gametocidal gene(s), its utilization will be difficult due to the selfish behavior of gametocidal genes.

Download Full-text